Lung Volumes and Their Significance for Pharyngeal and Esophageal Swallowing Function

Abstract

Subglottic airway pressure is generated during each swallow and this supports the probability that subglottic mechanoreceptors function as part of the overall afferent collage of signals that guide motor output. Lung volume at swallow onset, lung recoil forces, and chest wall compliance are all important factors that combine for the generation of sufficiently positive subglottic air pressure during the pharyngeal swallow. Higher lung volumes at swallow onset may also be advantageous to the esophageal pressure gradient during esophageal bolus transit. Patients with impaired lung-thoracic unit recoil and disordered breathing/swallowing patterns may not only benefit from learning to swallow during early exhalation, but may also need to start at a higher lung volume in order to compensate for reduced recoil effects on swallowing function.